Pulp molding apparatus



Aug. 9, 1960 H. A. WQLTER PULP MOLDING APPARATUS 3 Sheets-Sheet 1 Filed May 10, 1957 Aug. 9, 1960 H. A. WOLTER PULP MOLDING APPARATUS 3 SheetsSheet 2 Filed May 10, 1957 lllllllllllllll'illl Aug. 9, 1960 Filed May 10, 1957 H. A. WOLTER PULP MOLDING APPARATUS 3 Sheets-Sheet 5 PULP MOLDING APPARATUS Harry-A. Wolter, Akron, Ohio, assignor to Diamond National Corporation, a corporation of Delaware Filed May 10, 1957, Ser. No. 658,409 A v 1s Claims. 4 (Cl.-162-'392) This invention relates to pulp molding apparatuspand more particularly to an improvement in apparatus for.

successively molding pulp articles.

In the manufacture of molded pulp articles by the usual process of suction molding the articles from a water slurry of pulp fibers, it has been customary to employ a rotary carrier having a plurality of foraminous forming dies mounted on its periphery, which dies are subjected to suction internally as they are advancedsuc-1 cessively through a vat containing the slurry during rotation of the carrier. This action causes layers of'wet pulp'fibers to be extracted from the slurry and deposited on the molds, thereby forming initially molded articles, known as preforrns. In order to extract some of the excess moisture from the wet pulp preforrns, the suction applied to the molds is continued as the molds emerge from the slurry and advance successively upward'there' above during the continued rotation of the mold carrier. A; a predetermined point above the slurry, a transfer device, which is usually of the rotary type also, successively removes the 'preforms from the moldsand-transfers them to a' dryer. a

Such rotary multiple die type molding apparatus is particularly suitable for high speed production of large quantities of relatively non-complex, small, low unit cost molded pulp items, such as pie plates and egg cartons. However, the high cost of this equipment represents such Fig. 2 is a corresponding view of the apparatus illus- A trated in Fig. 1, but shown at a subsequent stage of the molding operation; V

Fig. 3 is another view corresponding to that of Fig.

1, but showing the apparatus at an intermediate state, of the molding operation subsequent to that viewed in Fig. 2;

Fig. 4'is still another view corresponding to Fig.

but showing the apparatus in a subsequent position at the completion of that stage of the molding operation shown in Fig. 3; and n Fig. 5 is a plan elevation view of the apparatus at the,

stage of the operation shown in Fig. 1.

' Apparatus embodying the invention features a simpli fied structural organization operating with an improved type of simple mechanical movement. A foraminous molding die 10 secured to a movable head 12 is periodically dipped intoan open-topped vat 14 containing pulp slurry. A flexible hose 16 connects the die head 12 with a source of suction (not shown), and suitable automatic controls for the application of the suction are.

provided. The suction is applied internally to the die 10 during its immersion in the pulp slurry contained in the vat 14 to cause pulp fibers to be extracted from the slurry and deposited in a layer on the outer forming face ofthe die 10, thereby forming an initially molded article 7 known as a preform. The molding die 10 cooperates with a compression die 20 to compress the pulp preform therebetween, thereby completing the molding of the pulp article and at the same time extracting some of the v excess moisture therefrom.

The compression die 20 is properly shaped to receive and mate with the molding, die 10 when these dies are broughtinto compressing relationship. The die 20 is supported on amovable head 22 which is mounted for horizontal reciprocation to bring these dies into mating a'l'arl'ge investment to be amortized, that only such large. 1

relationship, andthe head 12 likewise undergoes horizon- -tal reciprocation to carrythe die 10 into such relationship. An important feature of the present invention is the fact that the dies 10 and '20 undergo straight line horizontal reciprocation and are held disposed in parallel vertical planes facing each other while they are moved toward and away from each other in effecting the com pression action. .g

' Horizontal reciprocation of the dies 10 and 20 may be accomplished in any suitable mannen In the illus trated embodiment'of the invention, the die head 12 is the principal reasons for the large investment involvedin 1;;

the rotary multiple die type molding apparatus. Although simplified apparatus of the general type'employing only a singlefpair of dies has been known in the pastjnone of such apparatus has been entirely satisfactory.

object of this 'invention' isto providenew; and

improved'pulp molding-apparatus. l

Another object of the invention'is to provide a more eflicient, simplified, and inexpensive pulp molding apparatus of the type embodying only a single pair of cooperating dies.- 1 v Stil1 another object of the invention is to provide a ew and improved mechanical movement for a single pair of cooperating diesin a pulp molding apparatus. 3

;Qth er-objects and the nature and advantages of the of cam instantinvention will beapparent from the following description taken in-conjunction with-the accompanying drawings, whereinp. 7. .1

Fig. 1 is a longitudinal vertical section of pulp molding aprar smb a r position at one stage of a molding operatronp the invention, shown in its operating provided with a pair of lugs 24 (Fig. 5 which are engaged by a pair of clevises 26 formed on one end of a pair of oscillatable levers 27, At the other end of the levers 27 a horizontal shaft 28 secured'thereto provides a pivot for the oscillatory motion. Any suitable mechanical means may be employed to impart oscillatory motion to the shaft 28 to reciprocate the die head '12 therewith. In a similar manner, on thedie head 22 a pair of lugs 30 are engaged by a pair of clevises 32 formed on one end of a pair of oscillatable levers 33, which are secured at their other end to an oscillating horizontal shaft 34.

. Opposite ends of the die head 12 are provided with a pair of projecting arms 36, each of which carries pairs of cam rollers 38 and 39. The rollers 38 ride in a pair track slots 40 which are perfectly straight and horizontal for a substantial portion of their length, but they have an upwardly curved section 42 at their right hand end, as viewed in Figs. 1 to 4, inclusive, and the rollers 39 ride in a pair of'cam track slots 44- which are.

length It is evident that as the rollers 38 and 39 travel from left to right along the slots 40 and 44, respectively, during horizontal reciprocation of the die head 12, the die head 12 first moves in a straight horizontal line away Pir e .Aug. 9,19 0

from the compression die 20 from the position shown in Fig. l to the position shown in Fig. 2, and then the die head 12 turns downwardly through an angle of 90 tothe position shown in Fig. 3. The turning motion-of thedie head 12 is caused by the divergence of, the slots 40 and 44 at the right hand end thereof, Where. the up.- wardly curved section 42 of the slot. 40 is located.

In the next stage of the molding operation the die. is lowered and immersed into the pulp slurry contained in the vat 14, and any suitable mechanism may be provided for this purpose. In some instances it may be advantageous to immerse the molding diev with a perfectly straight line vertical reciprocatory movement, while holding the die facing its immersed position in order to attain a perfectly uniform thickness of deposition on the forming face of the die. However, in most instances some slight deviation from a perfectly vertical path is acceptable, as is the case in the operation of the illustrated embodiment of the invention. 7

. The molding die 10 is reciprocated into and out of the vat 14 by means ofa pair of rocker arms 50 having one end thereof secured to an oscillatable horizontal shaft 52. The other end of the arms 50 is designed to provide support structure for the horizontal shaft 28 on the upper portion thereof, and in the lower portion of this end of the arms 50 the cam track slots 40 and 44 are formed. The pair of arms 50 may be joined by a connecting rod 54 to provide structural rigidity, and a stop 56 may be provided to limit the upward movement of these arms. Oscillatory movement of the rocker arms 50. immerses the molding die 10 by moving it alternately between the position shown in Fig. 3 and the position shown in Fig. 4.

The horizontal reciprocation of the compression die also alternates with a 90 turning motion, but in this case no vertical reciprocatory motion is necessary, since the molded pulp articles successively produced are merely dropped onto an endless conveyor belt 69. Atfoppositc ends of the die head 22 a pair of projecting arms 62. each carry pairs of cam rollers 64 and 65. The rollers 64 ride in a pair of cam track slots 66 which are perfectly straight and horizontal for a substantial portion of their length but have an upwardly curved section 67 at their left hand end, as viewed in Figs. 1 to 4, inclusive, and the rollers 65 ride in a pair of cam track slots 68 which are perfectly straight and horizontal throughout their entire length. As the rollers 64 and 65 travel from right to left along the slots 66 and 68, respectively, during horizontal reciprocation of the die head 22, this die head first moves in a straight horizontal line away from the molding die 10 from the position shown in Fig. 1 to the position shown in Fig. 2, and then the die head 22 turns downwardly through an angle of 90 to the position shown in Fig. 3. The earn track slots 66 and 68 are formed in a pair of parallel vertical supporting plates 70 which are joined by a horizontal connecting rod 72, and which provide support for the shaft 34.

In Fig. 4 a molded pulp article 74 is shown resting on the conveyor belt 60 directly beneath the compression die 20 from which the article has just been dropped. Suction applied to the head 22 through a flexible hose, 76 holds the pulp article 74 in the die 20 until release of the suction allows the article 74 to drop onto the conveyor belt 60. The successive articles produced, such as the article 74, are carried by the belt 60 to a suitable final drying and finishing apparatus (not shown).

In one complete cycle of the molding operation, the molding die 10 and the compression die 20 simultaneously move through the successive stages illustrated sequentially in Figs. 1 to 4, inclusive, and thence back again to the stage shown in Fig. 1. Once during each cycle the molding die 10 is immersed in the pulp slurry contained in the vat 14, and the die 10 is then elevated above the slurry by movement of the rocker arms 50 until they strike the stop 56. Next, the die heads 12 and 22 are turned through the angle, thereby being brought into alignment facing each other, and they are then advanced toward each other in a straight line horizontal movement until they mate in compressing relationship, as shown in Fig. 1. The molded pulp article is then transferred from the die 10 to the die 26 by suitable manipulation of the suction applied internally to these dies, and a blast of compressed air may be applied internally to the die 10 to assist the transfer operation. The dies 10 and vanced in successive stages. back from the positions in which they are viewed in Fig. 1 to the positions shown in Fig. 4, resulting in release of the moldedpulp article 74 from the die 20 to drop it onto the conveyor belt 60.

At the completion of each molding operation the molding die 16 may be washed with fresh water sprayed from a plurality of nozzles 76 A haflle 78 may be mounted below the nozzles 76 to prevent the fresh Water spray from diluting the pulp slurry contained in the vat 14. The baflle 78 may be made retractable to enable it. to move out of the path of. the molding die 10 at the proper moment during each horizontal reciprocation of this die.

Although the invention has been illustratedand described with particular reference to only a single pair of.

cooperating dies, it is to be understood that each of these dies may be of the multiple type. That is, a plurality of individual dies may be mounted side by side for movement as a group on a single die platen.

It will be obvious to those skilled in the art that various changes may be made without departing from the,

spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. Pulp molding apparatus, comprising a molding die having a foraminous forming face designed to form pulp articles by deposition of pulp fibers from a slurry thereof, means for vertically reciprocating the molding die between a molding position immersed in pulp slurry and an elevated position above the slurry, said molding die f0rming face being disposed generally horizontally and facing its immersed position during: its reciprocation into and out of the slurry, a compression'die movably mounted ad iacent to said elevated position for cooperation with the molding die, meansv for turning the molding die and the compression die to bring them, into alignment facing each other above the slurry, and'means for horizontally recip rocating both of these dies to bring them into mating relationship, thereby compressing a molded pulp article thcre between.

2. The apparatus defined by claim 1 in which the molding die and the compression die are turned simultaneously through an anglev of 90, and these dies are horizontally reciprocated while. disposed in vertical planes facing each other.

3'. Pulp molding apparatus, comprising a single molds ing die having a foraminous forming face designed to form pulp articles by deposition ofipulp fibers from a slurry thereof, means for vertically reciprocating the molding die between a molding position immersed in pulp slurry and an elevated position above the slurry, a-single compression die mounted pivotally adjacent to said elevated position for cooperation with the molding die, means for turning the molding die and the compression die to bring them into alignment facing each other above the slurry, means for horizontally reciprocating both of these dies to bring them into mating relationship; thereby compressing, a molded pulp article therebetween, a conveyor mounted below the compression die for successively removing the molded pulp articles produced, and'rneans for turning the molding die and the compression the after they have moved apart a predetermined distance to face 7 them downwardly generally toward the slurry and. the

conveyor, respectively.

24) are then ad- 4. The apparatus defined by claim 3 in which the mold ing die is turned through an angle of about 90 above the slurry while the compression die is simultaneously being turned through an angle of about 90 above the conveyor.

5. The apparatus defined by claim 3 in which the molding die and the compression die are turned simultaneously through an angle of about 90 above the slurry and the conveyor. respectively, and these dies are simultaneously horizontally reciprocated while disposed in parallel vertical planes facing each other.

6. Pulp molding apparatus comprising a single molding die having a foraminous forming face designed to form pulp articles by deposition of pulp fibers from a slurry thereof, a movable die head supporting the molding die, means for vertically reciprocating the die head and the die carried thereon between a molding position immersed in pulp slurry and an elevated position above the slurry, a single compression die mounted adjacent to said elevated position for cooperation with the molding die, a second movable die head for supporting the compression die, means for simultaneously horizontally reciprocating the two die heads to bring the dies into and out of compressing relationship with each other, the dies being held facing each other during such reciprocation, cam means for turning the die heads downwardly through about a 90 angle after they have moved apart a predetermined distance, and conveyor means mounted below the compression die for successively carrying away the molded pulp articles produced.

7. The apparatus defined by claim 6 in which the molding die and the compression die are turned simultaneously through an angle of about 90 above the slurry and the conveyor, respectively, and these dies are simultaneously horizontally reciprocated while disposed in parallel vertical planes facing each other.

8. Pulp molding apparatus comprising a single molding die having a foraminous forming face designed to form pump articles by deposition of pulp fibers from a slurry thereof, a movable die head supporting the molding die, a pair of oscillatable rocker arms for supporting the die head, said arms being adapted to vertically reciprocate the die head and the die carried thereon between a molding position immersed in pulp slurry and an elevated position above the slurry, a single compression die mounted adjacent to said elevated position for cooperation with the molding die, a second movable die head for supporting the compression die, means for simultaneously horizontally reciprocating the two die heads to bring the die into and out of compressing relationship with each other, the dies being held facing each other during such reciprocation, a plurality of cams mounted on the die heads and movable along cam tracks during reciprocation of said heads, said cam tracks having perfectly straight horizontal portions for guiding the heads in straight line horizontal reciprocation while being held facing each other until they are spaced apart a predetermined distance and said tracks having curved portions for turning the heads downwardly through about a 90 angle after they have moved apart said distance, and conveyor means mounted below the compression die for successively carrying away the molded articles produced.

9. The apparatus defined by claim 8 in which the molding die and the compression die are turned simultaneously through an angle of 90 above the slurry and the conveyor, respectively, and these dies are simultaneously horizontally reciprocated while disposed in parallel vertical planes facing each other.

10. The apparatus defined by claim 8 in which the cam tracks for guiding the die heads are formed on the os- 6 cillatable rocker arms, and a plurality of oscillatable levers for horizontally reciprocating the heads are also mounted on the rocker arms.

11. The apparatus defined by claim 8 in which a plurality of spray nozzles are mounted adjacent to and directed toward the molding die in its elevated position for washing this die at the completion of a cycle of the molding operation, and a battle is mounted beneath the nozzles to prevent dilution of the pulp slurry.

l2. Pulp molding apparatus comprising a single movable die head supporting a foraminous molding die on which pulp articles are formed by deposition of fibers from a slurry thereof, means for supporting the die head and adapted to vertically reciprocate said head between a molding position wherein the head is lowered to immerse the die in pulp slurry and a compressing position wherein the head is elevated above the slurry, a second single movable die head supporting a compression die adjacent to said compressing position for cooperation with the molding die, both of said movable die heads being mounted pivotally and adapted to turn through an angle of about to bring them into alignment facing each other when the molding die has been elevated to its compressing position, means for simultaneously horizontally reciprocating the two die heads to bring the dies thereon into and out of compressing relationship with each other, cammeans for maintaining said dies disposed in parallel vertical planes facing each other during such reciprocation and for turning the heads through said angle of about 90 after they have moved apart a predetermined distance during such reciprocation, and conveyor means mounted below the compression die for carrying away the molded articles produced.

13. Pulp molding apparatus comprising a single movable die head supporting a foraminous molding die on which pulp articles are formed by deposition of fibers from a slurry thereof, a pair of oscillatable rocker arms supporting the die head and adapted during oscillation to vertically reciprocate said head between a molding posi tion wherein the head is lowered to immerse the die in pulp slurry and a compressing position wherein the head is elevated above the slurry, a second single movable die head supporting a compression die adjacent to said compressing position for cooperation with the molding die, a pair of support members on which said second die head is movably mounted, both of said movable die heads being mounted pivotally and adapted to turn upwardly through an angle of about 90 to bring them into alignment facing each other when the molding die has been elevated to its compressing position, means for simultaneously horizontally reciprocating the two die heads to bring the dies thereon into and out of compressing relationship with each other, a plurality of cams carried by the die heads and movable along cam track slots formed in the supporting members and in the rocker arms on which the heads aremounted, said cams and slots cooperating to maintain the die heads disposed in parallel vertical planes facing each other during reciprocation thereof and to turn the heads downwardly through said angle of about 90 after they have moved apart a predetermined distance during such reciprocation, and conveyor means mounted below the compression die for carrying away the molded articles produced.

References Cited in the file of this patent UNITED STATES PATENTS 1,158,634 Chaplin Nov. 2, 1915 1,880,458 Morris Oct. 4, 1932 2,559,945 Chaplin July 10, 1951 

